#include <func.h>
int nonblock(int fd)
{
    int flag;
    flag=fcntl(fd,F_GETFL);
    flag|=O_NONBLOCK;
    flag&=~O_NONBLOCK;
    fcntl(fd,F_SETFL,flag);
}
int main(int argc,char *argv[])
{
    char buf[6]={0};
    sleep(3);
    nonblock(STDIN_FILENO);
    read(STDIN_FILENO,buf,sizeof(buf));
    printf("%s",buf);
    return 0;
}

